clutch fail essay

[kaleb]

Morning all!

So I'm riding back West from a weekend in London, pleased with the excellent time I've made, when just outside my homecity Bristol I get a fairly sudden loss of power. I mean she drops from 80 at 6k revs to 50 at 7k+ with some unhealthy noises to boot. So I pull over, wondering what I've done. Ok I'd been riding for an hour at 80 - 90 but I gather that's nothing for a well-maintained (?!) brick...

The bike has 68k on the clock and as far as I can gather from the service history she's never had any new clutch parts (except a cable). She's been running well recently, except for an occasional wheezing groan on acceleration (especially under load) which sends a shudder right through the foot pegs. This groan has been increasing in frequency the last few hundred miles, and I had been planning to take her somewhere for diagnostics in the next week or two (honest!).

So now from a standstill she won't do more than 20mph in any gear and that requires revs of 6-7k. Smells like hot metal, and, crucially (pleased I noticed this!), she'll freewheel despite being in gear. Needless to say I didn't ride her any further than just off the motorway where we bade farewell until last night a pal and his van took her to my workplace where I have, helpfully, a woodworking workshop... I did speak to the local BMW approved garage and they want 500 sterling just to replace a friction plate, but of course it could be rather worse than that.

SO. In a fit of optimism I've ordered

new friction plate
new diaphragm spring
new pressure plate
new cover plate
all the washers and bolts
spline lube

from the helpful guys at Motorworks.co.uk

I can use the workshop between 4pm Saturdays and 8am Mondays. I have a couple pals with *some* mechanical nous who might be persuaded to look in on me. There are places at work I can store the bike and the parts, but I can't leave it all neatly laid out in the workshop during the week.

Feasible?


Gratefully,

Kaleb.
-------------------------

I had been about to write a more general post, explaining that I've booked a ferry for Betty (bęte noire) and I to France at the end of April. We'll have a month to see how far and back we can get - aiming for the Black Sea I suppose. I'm no stranger to long distance overland touring (www.iskaleb.com for my bicycle adventures) but this would be the first time motorised, and I was gonna ask for tips on tools and pre-maintenance.... I suppose that can wait until I get this clutch sorted!

[tsnap]

maybe a initial clutch hub failure, hence the smell warning you if impending problems, which eventually shredded, and complicated the situation.  Get it apart as soon as possible, to truly analyze the parts needed.

Definitely will need a good cleaning brush, soapy soultion, and tray to catch it all.  I would use a power washer.

tom

[Laitch]

It's feasible, Kaleb, but it's difficult enough without the constraints of space and time in your case.

If this were happening to my bike, I'd wash the engine and transmission with a dish soap—removing road grime with a brush, rinse with a hose running at a moderate flow to reduce the chance of water penetrating electrical components, then let it dry. Cleaning can help with identifying where fasteners are located and reduces the chance of grime's migrating around the assembly. If you can't do that, clean as you go to the extent you can.

You'll know the story only when you detach the transmission.

All parts except for the rear wheel could be placed in a couple of large bins. Taking photos at each stage records how many and what type of fasteners were with which component. I put the fasteners in lidded plastic boxes so they won't be scattered on the floor. Muffin tins work nicely to segregate parts as long as they don't get upended during the work.

Have a relevant manual at the ready, watch some videos about clutch service and failure. Here is and here is service. There are others, too. Watch the entire replacement video a couple of times and read the manual's diagnostic and replacement procedures a couple of times before you begin. Make an inventory of the tools required before you start. Be patient with seized fasteners; don't try to wring them off in one go. Plenty of advice about that written on this forum.

If takedown shows that the repair and reassembly is possible, you'll need spline grease. Check the forum for spline lube threads and take your pick. Have some assembly lube and anti-seize compound for reassembly.

The weekend could be enough time if you're well organized and don't need other parts. You'll need to be mindful of sawdust getting into things. You'll need to transport the front end of the bike back and forth to the shop if you can't sort this in the allotted hours and there's no room for it there. There are photos in the Projects and What Did You Did To Your Motobrick Today ?sections here of how members rig bikes for takedowns like this.

Your positive attitude and determination will serve you well, but sometimes circumstance puts repair beyond our own abilities. When that happens, learning who are the best mechanics specializing in BMW and K-bikes is essential. Dealerships aren't the only choice.

[tsnap]

I have done some repairs by strapping the bike to a trailer.  You can move the trailer in and out of a garage door, and keep your tools and parts organized and in one place.  The trailer becomes your workbench.  an open trailer can be covered with a big tarp when outdoors.

[Martin]

When I do any large job on any vehicle, I place the pertinent bolts in a zippy bag and cable tie them to the part with reusable cable ties . If needed you can write a description on the bag. You also might want to look at getting a clutch alignment tool, I have made my own on a metal lathe but if you have access to a wood lathe you could make one out of hardwood with an 6mm metal rod pushed into it for the final bit. measurements are to be found in the Haynes manual in the clutch section. It is also possible to line the clutch by eye ( if you have a good eye ). If the clutch is intact it is very important to mark the position of each part so that on reassembly you can realign in the same position ( white paint pen works well ).This job is not as daunting as it seems and the procedure is well documented. While you are in there you might want to replace the rear main & gearbox input seals as well as the clutch rod boot. A standard time to replace a clutch under normal circumstances is about 5 hours.
Good luck Martin. 

[The Mighty Gryphon]

If you start Saturday at 4 I would think you could easily be looking at the clutch on a bench that evening before you quit. 

With all parts at hand you could have it all put together on Sunday. 

You will need a clutch nut and o-ring.  The old o-ring will be destroyed when you pull the clutch apart and you can't reuse the nut.  BMW also advises that you replace the 6 bolts that hold the clutch pack together.

You will need a large breaker bar and a 30mm socket as well as a torque wrench to get the nut tightened properly.  I like ziplock sandwich bags for fasteners.  I use a sharpie pen to label what the fasteners are for. 

Good idea to do a complete spline lube all the way back to the final drive.  Slap some new rear brake pads in there as long as everything is apart.  Only adds another 10-15 minutes to the job. 

[kaleb]

Hi everybody. It's really encouraging to get such detailed advice so readily. Thank you!

In fact its the Easter holiday next weekend, so I can work through from Thursday evening until Monday night. Loads of time!

I've ordered all the various lubes and greases, confirmed that I'm getting all the necessary replacement bolts and washers with the clutch parts, and have earmarked several evenings between now and then to watch the videos and read my Haynes on clutch renovation. Oh and good idea on the brake pads - they need changing anyway, thanks Gryphon, so I've ordered some of those, and the motoworks had the clutch alignment tool for not-too-much so I got that, too, thanks Martin.

Question, Martin, about the "rear main & gearbox input seals" - are they these? :
http://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=ENA60456
http://www.motorworks.co.uk/vlive/Shop/Parts.php?T=6&Q=ENA60389

The guy at motorworks seemed to think these would be fine just to clean down, lube and pop back in... The latter seems quite expensive, but it'd be a shame to find it perished and have to wait for a new one. Whaddya reckon? The clutch-rod boot is visible under the bike, right? That one looks fine.

Plenty of time before hand to get the engine scrubbed down, thank you Laitch, and yes to buckets, labels, photo-logging, zipties, baggies, tape, cardboard cut-out exploded diagrams with the bolts and washers stuck in their respective locations etc etc etc. An advantage of doing it at work is I can spend some time before hand experimenting with blocks/trestles/jacks to lift and secure the bike.

And I had a little catch up with my buddy last night who's recommending me a short shopping list of essential tools, together with a few that he'll loan me.

So thanks for the encouragement, I'll be sure to document as best I can and keep you all posted.

You'll hear from me sooner rather than later!

Cheers

Kaleb.

[Martin]

The only reason I suggested the seals be replaced, is do you want to do this job again if they do develop a leak after you have done the job.
The only reason I had to pull my clutch out at 140,000 K's was a leaking rear main seal. I did replace the clutch but it had minimal wear, but only replaced because it had to be special ordered. If you are comfortable with not replacing the seals and they look fine leave them. The seal numbers are correct. While you have the bike apart you might want to consider fitting a grease nipple to the clutch pivot arm. The arm is subject to lots of water and road scum installing a grease nipple allows you to push the crap out and stop it getting in.
Regards Martin.

[The Mighty Gryphon]

Make sure you get a couple of those o-rings.   They are cheap and you cannot get the clutch basket off without destroying the o-ring, and if something comes up that requires you pull the basket a second time it will save a lot of time to have another o-ring readily at hand.   Don't ask me how I found that out.   

Sounds like you have your act together.  Oh, and you might want to have a box of those blue nitrile rubber gloves to keep your hands clean.   Good luck!!!

[Elipten]

Make the long bolts to slide the tranny back from the engine

[kaleb]

Hi Elipten,

The more I read about the process, the more I feel I need to understand what you mean here!

I gather some 8mm bolts, 125mm long, with the hex heads cut off (?) will somehow assist me in securing the transmission block in its correct position while I carry out my work on my clutch, and will enable the accurate mating of the transmission and the clutch when I'm reassembling.

I can find lots of discussion about what bolts are appropriate, right down to several decimal points of diameter accuracy, but nowhere a picture of where and how they go in.

Perhaps it'll be obvious when I get to that stage, but so I'm on the right track, does anyone have a photo, and, would some of these be the right thing for me to be adding to my inventory?

http://www.screwfix.com/p/easyfix-stainless-steel-a2-stainless-steel-threaded-rods-m8-x-300mm-5-pack/4380j


It looks like this are the 'correct' way of doing it:

http://www.ebay.ie/itm/BMW-Transmission-Set-Guide-Drift-Pin-83300401812-K100-K75-K1100-R1100-R1150-/272175745810?hash=item3f5ef04b12

?


Thanks for any clarity you can lend!

Kaleb.

[Laitch]

Using the guide pins is shown in the video about spline lube, Kaleb. Get to the point when they decouple the engine from the transmission to work on the splines and clutch. Those are the two headless bolts they screwed into the engine on which they slid the transmission from the engine. You can buy them or make them; just use bolts of the same size and thread pitch.

[kaleb]

Got it! Thanks, Laitch. They're just used to stop the weight of the transmission block damaging the clutch rod before you slide it back and off....

Some of the other tutorials/accounts I've looked at have said that it isn't necessary to detach the transmission from the swingarm, and that leaving that section intact saves labour. Any comment on that?

Another question I'm a little embarrassed to have to ask, but hey, is it necessary to drain the engine oil before I do all of this? Seems a shame as it wasn't so long ago I filled it up with the expensive stuff.

K

[Laitch]

Drain the oil. That makes the work seven pounds lighter. Detach the engine completely. Clean the splines thoroughly. Follow the video along with your manual but watch the video a couple of times all the way through this week. Read the procedure in the manual completely before starting. There will be some differences between the video and the manual. I'd go with Harris's methods. It's all straight forward nut-and-bolt work.

[rbm]

Some of the other tutorials/accounts I've looked at have said that it isn't necessary to detach the transmission from the swingarm, and that leaving that section intact saves labour. Any comment on that?

Speaking from experience, I'd say it's much easier to detach the swing arm from the transmission to do the job, if you are working alone.  That assembly weighs a lot and I found it to be a struggle to maneuver it into place while trying to support it.  I was performing this work alone at floor level; it might have been easier on a lift and definitely doable with assistance.

[Laitch]

Take the swingarm off as Robert suggests, Kaleb. Be thorough. You'll have plenty of time if you're well-organized, and you have plenty of time to get well-organized. No shortcuts.

[The Mighty Gryphon]

I've done this job 5 times in the past two years, so I have a bit of experience.

First, you don't need to drain your new engine oil, or the transmission oil for that matter.  The oils are contained in their respective units.

Remove the swing arm.  It makes moving the transmission twice as hard.  You will need to have it off in order to lube the splines on the transmission output shaft and the swing arm bushings anyway.

Some guys put a sawhorse under the tail section to hold the bike up when the centerstand is removed.  I have a stack of wood that I made by cutting a 2 x 8 into seven or eight 10" pieces.  The top piece of the stack will need a hole in it to clear the engine oil drain plug.  The stack works if you don't have a sawhorse, but you have to be more careful not to let the bike fall of the stack. 

The support bolts are 10mm x 100mm with the heads cut off.  No need for those screwdriver slots as you can spin them in with your fingers.  Put them on opposite sides of the transmission.  One near the alternator on the right side and the other just under the ignition coils on the left.

When you unbolt the transmission from the frame keep an eye out for the shim that may be between the frame and the transmission on the left side.  It has to go back there when you put things back together.

Use a metal handled acid brush to "paint" the lube lightly onto the splines of the transmission input shaft.  You can reach it with the brush when the transmission is slid back about 1 1/2".  You only need a tiny bit of lube.  If you slop a bunch on there it will get on the friction disc and your clutch will slip.  Just use enough to make the splines look darker.  Wear some of those blue nitrile gloves.  That spline lube is nasty dirty black stuff.

With the transmission in 5th gear you can rotate the input shaft by turning the output shaft.  Same thing to make the splines line up when you put things back together.

All in all. it's not a bad job other than the pain in the ass of dealing with the ABS modulators.  Even the first time you should be able to get it all done and buttoned back up in about 5-6 hours.  While you're in there, it's a good idea to pop in a new set of rear brake pads.  You can buy a whole set of organic /kevlar pads for the front and back for around $15 on eBay.  When you're done it's really nice to know that the whole back end of the bike is mechanically right.

Good luck and enjoy yourself.  Think of it as foreplay to get the bike ready for great riding.

[Elipten]

Looks like everyone gave you great advice.  Sorry it did not reply but I have been traveling on not on line.

[kaleb]

Evening y'all

Thanks so much for all the advice. From having been so daunted I can now hardly believe that I'm actually looking forward to getting wrenching tomorrow.

I've built a front wheel stand with ratchets to lock down the forks, played around with a trolley jack and blocks to see what works well, charged up my old point'n'shoot camera and bathed all the suspect  bolts in WD40...


Speaking of which: I'm not everso keen to go near these!





Am I right in thinking I can get away with removing just the muffler, here:




And if so, will I need to order a new pipe-to-muffler gasket?


Cheers, enjoy the Easter holiday

K

[tsnap]

got autopsy music?

tom :musicboohoo:

[rbm]

No need for the mica gasket sold by BMW. Use high temperature sealant or muffler cement.  Read this thread.

[Laitch]

Speaking of which: I'm not everso keen to go near these! Am I right in thinking I can get away with removing just the muffler, here . . .

Then don't go near them, Kaleb, not if you're working on a K75. The video makes that clear. Better take another look at it. Replace the WD40 treatment with a 50/50 solution of ATF/Acetone for releasing seized fasteners.

Work with finesse, brace yourself and keep a cool disposition so you won't shear the head off a seized bolt in frustration. It's then that the real fun begins and the ticking clock gets a lot louder.

[kaleb]

Evening gents

I've had a good day, with a few obstacles.

I only had to angle grind one bolt off (the one holding the muffler clip).

And all my splines look in good nick, so that's a relief.

And it only took an hour's grunting to get the swing arm three-bolted plate off.

I've gotten the clutch exposed. I'll leave the marking and plate removal 'til tomorrow now.

But I have one puzzle:

The clutch push rod is still protruding from the centre of the clutch. Chris Harris' appears to come away with the tranny, as is clearly visible sticking out of the block once he's removed it.

Mine looks like this:



No rod.

While my clutch looks like this:



Any ideas?


Oh and I found a load of metally-fibred crud between the tranny and the clutch housing, so I'm guessing (hoping) that's my catastrophically failed friction plate....


Good night hey, happy easter!

K

[kaleb]

D'oh! Sorry, I'm being a plonker. Should've been reading Haynes alongside the video, of course it's a k75 thing, different to the 100 in respect of the rod sliding out with the tranny, or not.

All good then!

[The Mighty Gryphon]

The clutch push rod should normally come out with the transmission.  It should not hang in the clutch like that. 

Can you easily pull the rod out of the clutch?  If not, there is a problem there.  It could be a misalignment between the friction plate and the diaphragm spring.   Or, it could be that the pilot on the end of the push rod has been bent during an earlier transmission removal. 

The bent rod could possibly be cause of the clutch failure.  By not being able to smoothly slide through the spring plate it may have interfered with the clutch action preventing proper action and burning the friction material.

Even the slightest bend in the end of the rod will cause a problem.  I think you can check for bend when you reassemble the clutch with the alignment tool.  Once all the clutch parts are aligned, it should be easy to slide the pushrod into the clutch assembly.  If not, you will need to replace the rod or attempt to straighten it.  You may be able to file away a very slight bend that can't be straightened. Just get the high spot that causes the binding, being careful not to touch the last cm. at the end that is held in the pilot shaft. 

Here's hoping you don't need a new rod, as that will mess up your plan to be done before Monday.